A Rare Cause of Hypokalemic Rhabdomyolysis-Gitelman Syndrome

Abstract

Gitelman syndrome (GS) is an autosomal recessive salt-losing tubulopathy, characterized by hypokalemic metabolic alkalosis, hypomagnesemia, and hypocalciuria, and is usually caused by mutations in the SLC12A3 gene encoding the thiazide-sensitive sodium chloride cotransporter (NCCT).We present a 25-year-old Chinese female who suffered from progressive muscle tenderness and muscle weakness in the bilateral lower extremities for several days and was admitted to the neurologic ward under the impression of myositis at first, but turned out to be an inherited disease of renal potassium loss. In view of her high transtubular potassium gradient (5.6), hypocalciuria (daily urine Ca excretion: 44 mg/d, urine Ca/Cr molar ratio: 0.043) and higher fractional excretion of magnesium (FEMg: 6.58%), she was then diagnosed as having Gitelman syndrome (GS). Genetic sequencing study showed that she had compound heterozygous NCCT mutations (T60M from her father and W844X from her mother).Since the prevalence of heterozygous NCCT mutations is relatively higher in Taiwan, hypokalemic rhabdomyolysis caused by GS still need to be considered in non-hypertensive hypokalemic patients with hypomagnesemia and hypocalciuria.